Having a lane for traffic in each direction and a center lane for passing (adjective)
WordNet. Princeton University. 2010.
Use "three-lane" in a sentence
"Driving in general is surreal as you can find yourself on a three-lane superhighway set against majestic vistas and courteous drivers who actually use their turn signals."
"Then there is a drive for several miles along a new three-lane highway."
"The latest and greatest example is Andy Stanley's Northpoint Community Church, who recently raised five million dollars to build their own three-lane overpass so that they could keep parking-lot-exit-times under thirty minutes."